Several applications are known in which connections need to be provided underwater, such as electrical connections or optical connections. Examples include a subsea installation for the production of hydrocarbons from a subsea well, in which different components of the subsea installation may need to be connected for power transfer and/or data communication. Such connections may for example comprise a connection from a topside installation, such as a floating or fixed platform, or from an onshore site to a subsea component, e.g. by means of an umbilical or a subsea cable. Other connections include electrical connections between different type of subsea equipment, such as a connection between a subsea transformer and subsea switchgear, a data connection between different control modules or between a hub and a satellite well. In some configurations, such connections need to transport significant amounts of electrical power. It is desirable to provide connectors that are capable of transporting electrical power at high voltages.
Subsea electrical connectors usually have two connector parts that can be mated, for example a plug part and a receptacle part, which may also be designated as a male part and a female part. At the forward end of the connector part, the connector part is mated with the respective other connector part. Wet-mateable connectors are capable of being mated in a subsea environment at several hundreds or even more than one thousand meters of water depth. On the other (rear) end of such connector, the connector must somehow be connected to an electrical conductor, such as the conductor of a subsea cable or to the conductor of a pin that is provided in the wall of a subsea enclosure. Such termination and connection is usually provided in a so called cable gland. The termination is critical for the establishing of a good electrical contact between for example such cable and the electrical contact of the connector, e.g. a connector pin. Furthermore, when the connector is operated at high voltages, for example an excess of ten thousand volts, the termination must be capable of withstanding such high voltage potential differences between the energized conductors and the system's earth.
A termination for a connector is for example described in the document EP 2 811 584 A1. In such connector, a gland is assembled onto the connector rear part, the connector comprising a pin. A crimp provides an electrical contact between the back of the connector pin and the conductor of the cable. Insulation between the high voltage elements and the connector earth may then for example be provided by a filling of the connector with dielectric fluid, which may for example be a polymer material that can be cured, for example an encapsulating rubber, it may also be a gel or an oil.
Such filling has to occur with high precision in a clean environment, since any pollution of the filling fluid may lead to problems with respect to the insulation. Any failures can result in a low insulation resistance, partial discharges, and at worst in an electrical breakdown of the insulators. It may thus take several attempts before a sufficient quality of the fluid fill is achieved. Furthermore, the fluid fill can take a relatively long time to perform, and additional time is required for curing. For example, this can amount to more than one day for a gel or for a setting elastomeric material. If the first fluid fill was not successful, additional long times are required to strip down the connector and to have a further attempt.
In particular, the termination between such pin and a cable by means of the cable gland often needs to occur onsite, for example on board a ship at sea or at the dockside. The reason is that the pin may for example be required to close and seal a relatively large subsea enclosure that cannot easily be transported to the manufacturing site of the subsea cable. Furthermore, such transportation would require a significant amount of time, and it may not have been decided on the configuration of cables and connectors which are to be used with the respective subsea device. Accordingly, in such onsite environments, the cleanliness and the quality of the fluid fill of the termination gland is difficult to control, and pollution and an insufficient quality of the fill can result. Furthermore, due to the required time for the fill, the filling of such connector requires resources and is cost intensive.